Vulcanizing molds for tires are composed, inter alia, of molded parts which together form the radially outer surface of the tire such as the tread, the shoulder region, the sidewalls and the bead region. The segments which form the tread are referred to as profile segments or molded segments.
The term “profile positive” comprises all the sipes of the profile as well as possible further sipes such as those for the insertion of lamellar plates for passenger cars and van tires.
The mold segments of vulcanizing molds for tires are fabricated from aluminum and metal. A person skilled in the art is sufficiently familiar with vulcanizing molds manufactured by casting methods and with the method described above for obtaining a casting mold.
The non-vulcanized green tire blank is vulcanized in the vulcanizing mold and transferred into its ultimate rubber-elastic state by rubber crosslinking reactions. In the process, the tire is given its profile configuration by the corresponding negative configuration of the molding areas of the mold segments. The term molding areas refers to those areas of the mold segments that give the tire blank its corresponding configuration.
It is advantageous for the tire performance, in particular for the snow and ice performance of winter tires, if the casing-shaped surface of the tire tread has a defined degree of roughness. The grooves of the tread profile which bound the raised profile elements should, on the other hand, be as “smooth” as possible in order to give the tire an impression of high quality.
United States patent application publication 2010/0282387 discloses that the molding areas of the profile segments of the vulcanizing mold have a plasma coating with a defined degree of roughness. The tire tread which is vulcanized with this vulcanizing mold also has, owing to the imprint of the plasma coating, a defined degree of roughness and performance which is improved thereby. A suitable plasma coating and the advantages which can be achieved therewith are described in the abovementioned document.
However, it is costly to provide every completely manufactured vulcanizing mold subsequently with a suitable plasma coating; in particular, if the raised webs of the molding area which mold the grooves of the tire tread are not to be provided with the plasma coating which has the degree of roughness.